The present invention relates to a method and system of fuel injector operation and more specifically a method and system of fuel injector operation for post injections.
Fuel injector operation and control can have a profound impact on an injector""s durability and long term performance. Further, injector operation and control can have a substantial effect on the engine""s performance and durability itself, as well on related engine systems, such as the electronic control module (ECM). For example, the timing and number of fuel injection events per engine cycle impacts emissions. Currently, many engine manufacturers are researching multiple injections per cycle in order to reduce emissions. Specifically, a pilot injection could be used to enhance combustion, while a post injection could be used to help after-treatment. Unfortunately, each injection requires the injector to cycle or actuate, which causes additional wear on the injector. Further, the ECM must generate an actuation signal every time a fuel injector needs to inject. Therefore, using a combustion strategy that requires a pilot, main and post injection, the ECM would be required to generate three signals. Each signal requires the ECM to use additional energy and simultaneously creates more heat which can impact the longevity of the system.
The present invention is directed to overcoming one or more of the above stated problems.
In one embodiment of the present invention, a method of controlling post injections in a multicylinder internal combustion engine having a plurality of fuel injectors comprises: selecting one of the of fuel injectors and increasing the injection quantity for the selected injector and selecting another of the plurality of fuel injectors and decreasing the injection quantity for that injector.
In another embodiment of the present invention, a method of controlling post injections in a multicylinder internal combustion engine having a plurality of fuel injectors which receive a total duration of injections signals during each engine cycle from an electronic control module is provided. The total duration of injection signals comprises the sum of the individual injection signal components including a pilot injection signal, a main injection signal and a post injection signal during each injection cycle. The method comprises the steps of: selecting one of the plurality of fuel injectors and increasing the total duration of injection signals for said selected injector; and selecting another of the plurality of fuel injectors and decreasing the total duration of injection signals for said selected another injector.
In a third embodiment of the present invention, a fuel injection system for a multicylinder internal combustion engine comprises: a plurality of fuel injectors and an electronic control module to control when the fuel injectors perform an injection event including a post injection, wherein the electronic control module sends an increased duration post injection signal to one selected injector and sends a decreased duration post injection signal to another selected injector.